44* M. Von Buch on Gabbro. 



from Mont Cimult, or Salamont, and' separating the valley 

 of Julier, from that of Err, appears to be principally formed 

 of serpentine and gabbro, resting on primitive schist, and 

 constituting a well characterised and extensive formation. 



Gabbro was known to artists, long before the time of 

 Saussure. The Grand Duke Ferdinand de Medicis, caused 

 numerous blocks of it to be transported from Corsica to 

 Florence in 1604, where it received the name of Verde di 

 Corsica, and where, under various forms, it ornaments the 

 Laurentine Chapel ; but none has been since brought from 

 thence, and the precise place of its occurrence was forgotten, 

 and it was not till within these few years, that Messrs. 

 Muthuon and Rampa§se, French engineers, again found itj 

 first in large blocks near the village of Stazzona, to the 

 north-west of Corte, and afterwards, in place, but always 

 accompanied by serpentine, in the high mountains of San 

 Pietro di Restino, which form a chain between Corte and 

 the sea. Thus there, as in Switzerland, gabbro forms a rock 

 of itself, and not a bed subordinate to another. In the 

 suite of rocks sent by M. Muthuon to the collection of the 

 Administration of Mines, the most insensible passage of 

 green diallage into schiller spar, is observable in the speci- 

 mens of gabbro. 



Saussure describes (§ 1313), a gabbro at the mountain of 

 Musinet, near Turin, the mode of occurrence of which he has 

 not observed, formed of white or lilack jade, and of diallage 

 sometimes green, at others grey ; M. Berger notices diallage 

 mixed with the semi opal of Werner (silex resinite) at Bal- 

 dassero, near Ivree : the native magnesia of Giobert occurs 

 there in small beds. 



A part of the mountains surrounding Brian^on and la 

 Grave in Dauphine, appears to be formed of gabbro; serpen*, 

 tine and talcose rocks are known to occur in the same moun- 

 tains, which also furnish the substance called Brian9on 

 chalk. 



The gabbro formed of jade and green diallage does not 

 appear to have been known to the ancients. That formed 

 t)f jade, felspar, and grey diallage, has, go the contrary 



